Making a good cup of espresso is often considered an art form. In addition to a powerful taste, a good cup of espresso generally has a layer of crema. Crema is the golden foam that should cover the top of the espresso. Several variables must be controlled to produce a good cup of espresso. These variables include the nature of the grind, the tamp pressure, the brewing temperature, the pressure, and the time.
Several types of portafilters are used today with espresso machines. Commercial portafilters may be made out of heavy chrome plated brass or similar types of materials. To use such a portafilter, an amount of coffee grinds is placed in the filter. The grinds then must be tamped down with an appropriate amount of pressure. The greater the tamp pressure and the finer the coffee grind, the greater the resistance to the water flow therethrough. Too little resistance provides a weak beverage with little crema. Likewise, too much resistance may cause an over-extraction and again little to no crema. Although opinions differ, many coffee lovers believe that the commercial portafilters provide the best beverage if done correctly. Drawbacks, however, include the use of an inadequate tamp pressure and the necessity to clean the portafilter.
Other types of known portafilters include pressurized portafilters. These pressurized portafilters only require the use of a light tamp because the espresso machine will only allow the water to pass therethrough when the appropriate pressure has been developed. These portafilters, however, also need to be cleaned regularly.
Finally, pod portafilters are also known. These pod portafilters use coffee grinds that are prepackaged in sealed filter paper. The pods are simply placed in the portafilter. The quality of the beverage, however, may not be adequate because of the aspect ratio of the pod and/or the nature of the filter paper. The aspect ratio may be too thin, i.e., the pod may be too thin compared to its diameter such that the water passes through the grinds too quickly. Further, the filter paper may not have a consistent resistance. The water may tend to travel through the paper and around the grinds rather than through the grinds themselves. These pod portafilters generally require less cleanup than the commercial or the pressurized portafilters, but the portafilter itself still must be cleaned.
There is a desire, therefore, for a portafilter that includes the ease of use found in pod portafilters while providing the superior coffee offered by a commercial portafilter. The portafilter should be easy to use and require little to no cleaning.